Evolving Air Quality Under the Changing Climate: Enhanced - - PowerPoint PPT Presentation

Evolving Air Quality Under the Changing Climate: Enhanced Understanding through Blue Waters

D J. Wuebbles and Swarnali Sanyal

Department of Atmospheric Sciences University of Illinois at Urbana - Champaign

Why Do We Need Air Quality Management?

WHO, 2018

Ø 7 million deaths per year due to breathing polluted air (WHO). Ø ~91% of people worldwide breathe polluted air

Considerations In Air Quality Management

Emissions Formation Dispersion Concentration Anthropogenic and natural sources

X Y Z

Gases and Particles

X+2Y = Z Z+Y = A

Chemical Transformation Reaction to sunlight and temperature Effects from weather & climate Impact of topography Exposure & Health Impacts

Impact Of Climate Change On Air Quality?

Ø Warmer temperatures leads to more O3 production. Ø Shifts in weather regimes like jet streams, Bermuda highs, storm activities and hydrologic extremes. Ø Effects of long-range transport across national boundaries from Mexico, Canada, Asia, and North Africa. Ø Increased wildfires increases O3 and PM. Ø Drier soils, more dust storms.

Dust

Surface Ozone Particulate Matter

Hg Oil Spill low jet upper jet LRT Wild fire

A Focus on Human Health: Exceedances

• Exceedance days = days when surface concentrations > ambient air

quality standard for ozone and PM2.5

• Exceedance days useful indicator of exposure
• United States, China and India are studied for Ozone and PM2.5 exceedance

events (historical, future RCP4.5 and RCP8.5 scenarios)

• Exceedance days measured compared to standards prescribed by the

United States and by the World Health Organization

U.S. Standard WHO Standard MDA8 (8 hour average) O3 70 ppb 50 ppb 24 hour average PM2.5 35 µg/m3 25 µg/m3

Project Objectives: Why Blue Waters?

Blue Waters enables high resolution simulations with the global climate system modeling with fully coupled atmospheric chemistry.

Ø Global climate-chemistry CESM model at 0.9o x 1.25o horizontal resolution Ø Determine impacts from global climate and emissions changes on global air quality to 2050 under multiple scenarios. Ø Additional sensitivity study for a clean energy future – no fossil fuel emissions by 2050.

O3 Exceedance Days Decreases for the U.S.

Historical 1990 - 2014 RCP4.5 2031 - 2060 RCP8.5 2031 - 2060 U.S. standard WHO standard

Ø Annual average exceedance days for historical and future climate scenarios over United States Ø Compared to U.S. standard, both the lower and higher climate scenario, exceedance days reduces Ø Compared to more stringent WHO standard, number

• f

exceedance days increases in case of the higher scenario (Days)

Exceedance Days for U.S. Megacities

WHO standard U.S. Standard

Ø Exceedance days higher for RCP8.5 scenario, except Los Angeles and Houston Ø Exceedances underestimated for land-

• cean boundary areas (e.g., Los

Angeles, Houston) Ø >60% days exceed U.S. standard for NY, Chicago and Denver for RCP8.5 scenario Ø Winter season showing an increase in exceedance days in the future (not shown)

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060

Historical 1990 - 2014 RCP4.5 2031 - 2060 RCP8.5 2031 - 2060 U.S. standard

O3 Exceedance Days Changes In South Asia

WHO standard

(Days) Ø Annual average exceedance days for historical and future climate scenarios over China and India Ø Compared to U.S.A standard, the number of exceedance days in China for lower scenario, but increases

• ver wester central China for higher

scenario Ø Exceedance days increases for both the scenarios

• ver

India. The Gangetic plain has the highest number of exceedance events

Exceedance Days for Megacities In China

WHO Standard U.S. Standard

Ø Exceedance days decreases for all the cities in the RCP4.5 scenario Ø In case of Chengdu (west central China) increases for RCP8.5 scenario Ø With WHO standard, all cities show significantly larger number of exceedance days

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060

Exceedance Days for Megacities In India

WHO Standard U.S. Standard

Ø Increases in future for both the scenarios Ø Monsoon has the least exceedance days, due to washout of pollutant Ø Delhi still has high % exceedance days during monsoon season

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060

PM2.5 Exceedance Days in U.S. Decrease

U.S. standard WHO standard Historical 1990-2014 RCP4.5 2031-2060 RCP8.5 2031-2060

Mean annual exceedance days for anthropogenic PM2.5 (does not include natural sources: dust and sea salt) Ø Total and human PM decreases in both scenarios. (Days)

Exceedance Days In Megacities In The United States

Ø Exceedances underestimated for land-

• cean boundary areas (e.g., Los Angeles,

Houston) Ø Total PM2.5 includes dust and sea-salt Ø # of exceedance days increases for Chicago and Denver in the future scenarios

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060 WHO Standard U.S. Standard

PM2.5 Exceedance Days Increase In South Asia

U.S. standard WHO standard

RCP 4.5 Historical RCP8.5

Mean annual exceedance days for anthropogenic PM2.5 (does not include dust and sea salt) Ø India: the number of days increases for both scenarios Ø China: the number of days increases in the high scenario

RCP4.5

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060

(Days)

Exceedance Days for Megacities in China

Ø Total PM2.5 includes crustal materials dust and sea-salt Ø Exceedance event increases only in Beijing for RCP8.5 Ø Exceedance days decreases further for both present and future when compared with the U.S. standard

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060 WHO Standard U.S. Standard

Exceedance Days for Megacities In India

Ø Total PM2.5 includes dust and sea-salt Ø Delhi (in the northern Gangetic plain) had the highest number of exceedance days for both scenarios Ø In case of Mumbai, total PM2.5 increases in the future scenarios (note that Mumbai is a coastal city with influence of sea-salt).

Averaged over : Ø Historical: 1990 – 2014 Ø RCP4.5: 2031 – 2060 Ø RCP8.5: 2031 – 2060 WHO Standard U.S. Standard

Clean Energy Scenario

Ø At present 80-85% of total energy comes from fossil fuel combustion and biomass burning Ø Clean Energy scenario Ø No emissions from fossil fuels by mid- century (2050), but still include emissions from use of biofuels, and from

• ceans

and

• ther

natural sources

Emissions

Clean Energy: Ozone Concentrations Decrease

Annual Average Concentration Mean Summer Concentration

RCP8.5 Clean Energy RCP8.5 Clean Energy Ø The hotspot regions remain the same Ø Eliminating fossil fuel emission reduces the burden of O3 precursors thus reducing overall surface ozone concentration

PM2.5 Improvement In Clean Energy Scenario

Total PM2.5 Anthropogenic PM2.5

RCP8.5 Clean Energy Ø PM2.5 reduces significantly over South Asia and Indo Gangetic plains Ø Change in total PM2.5 is dominated by sea salt and dust Ø Anthropogenic PM2.5 from biomass burning is reflected in high concentration found in mid-Africa

Clean Energy: Health Improves (Exceedances decr.)

Ø Exceedance days decreases globally Ø Surface ozone concentrations are reduced by 40-50% annually and in the summer by 30- 50%, reducing exceedance days over the hotspot regions by 70-100% Ø Total PM2.5 concentration reduces by 20% specially over South Asia Ø Removing fossil fuel completely improves air quality significantly throughout the planet Ø Exceedance days over northern Africa is dominated by dust

Color bar shows number of exceedance days

Conclusions

Ø Focused on health impacts of a changing climate on air quality

Ø How changing climate impact air quality in the United States, China, and India focusing on exceedance events for surface ozone and particulate matter Ø Impact of an idealized clean energy world on air quality in the mid-century

Ø For the high (RCP8.5) scenario, air quality degrades in India and in China and exceedance days increases from the present regionally Ø Air quality generally improves over the United States, even for the high scenario. Ø The clean energy future scenario results in a world with significantly improved air quality, resulting in a significant reduction in air quality related health issues.

Thank you!

Summary for Ozone

Ø Ozone concentrations decreases over the United States for all seasons in the lower scenario, but increases in different regions for summer and winter for the higher scenario. Ø In case of China, concentration decreases for all the season except winter in case of the lower scenario, but increases during all seasons. Ø In case of India for both scenarios, concentrations increase (except for monsoon). Ø Increase in exceedance days in high scenario for China and India, but decreases for United States. Ø There is an increase in exceedance days for winter and spring.

Summary for PM2.5

Ø PM2.5 concentrations decrease over the United States for both future scenarios, but increase in India Ø PM2.5 concentrations increase in China for the high scenario Ø Anthropogenic PM2.5 (as well as total PM2.5) also exceeds WHO standard (and U.S. standard) overall and in the megacities

Summary: Clean Energy Study

Ø Under the clean energy scenario, surface ozone concentrations are reduced by 40-50% annually and in the summer by 30-50%. Ø Anthropogenic PM2.5 shows a reduced concentration ranging between 40-75%. Ø For total PM2.5, annually a reduction by 10-20% is derived over South Asia. Ø Removing fossil fuel completely improves air quality significantly throughout the planet.